Sausage and cheesy omelettes and salad doesn't bad. Surely they have some plain chicken, fish or burgers you can take off the bun. Sweet potatoes are pretty cheap and you can microwave them in 3-5 minutes.
Also, maybe if you qualify for college aid, you might qualify for food stamps? (SNAP is I think what they call it now.) Also, see if any organizations give out free food boxes. You can give away the stuff you don't want to eat (lots of rice and cereal in those boxes) and keep the veggies, meat, etc.
Good luck to you!
As yodiewan said, just cut out the really bad stuff. It's ok if everything isn't organic/grass-fed/pastured. The important thing is to avoid the pasta/pizza/bread, etc. Now that I'm "all growed up" and not on such a restricted budget, I do buy organic/grass-fed/pastured, but I've also found that my grocery bills are much smaller. I try to hit the farmers market, and I bought into a Beef CSA with a friend of mine. In general, because I'm eating cleaner, I found I'm not hungry all the time like I used to be, so I eat less, and have to buy less. At first I thought it would be crazy expensive, but it hasn't been all that hard.
I second all the advice given on here. When you're using the meal plan and eating on campus... do the best you can. Cut out the crap and go with what's left. As for what you're purchasing yourself...
I'm a college student on a pretty tight budget as well but have managed to make Primal eating work by rearranging my shopping priorities (and luckily I've been able to do the grass fed/free range/wild caught etc. etc. thing).
First and foremost: cheap cuts of meat are your friend. Ground beef and chuck roasts (bone in is even better and usually cheaper) are your BFFs. I buy marrow bones and roast them for the marrow, and then boil the bones to make a stock (same with whole chickens and chicken carcasses. NEVER THROW THE BONES AWAY and always buy your meat with bones when you can)! Stocks and soups make everything stretch hella far and you can't beat the nutrition of bone broths... and include that offal, baby! You can get some darn good grass fed suet or pastured pork fatback and render your own tallow/lard for some fresh, amazing fat since pastured butter can run on the pricey side.
Don't forget your fish! You can get some nice wild-caught canned salmon for $2-3. Or humanely farm raised for even less. Canned fish = awesomeness for a college budget. Mix that can with an egg or two and seasonings of your choice and fry it up in some of that home rendered tallow and BAM - delicious salmon patty. Throw it on top of some salad greens or vegetables of your choice and you have a great meal for less than fast food """meal""".
Sorry, we're in college, so forget milk, yogurt and cheese since they're $$$ for your calorie/nutrition need if you still do dairy. Making your own yogurt is pretty awesome and I still do the occasional homemade yogurt of kefir batch but it's kind of a treat now that meat is taking up so much of my budget. And unless there are some nice berries on sale I barely do any fruit. Veggies are better anyway and you tend to get more bang for your buck.
Learning what's in season is innnnvaaaaluable (*slow read* since it's that important). And I'm going to reiterate the bone-in/whole chickens/BONE BROTHS since nothing makes for a cheaper and delicious Primal/Paleo meal than homemade soups and stews.
Last but not least - take advantage of sales. Fruits/veggies/meat, they all freeze like professionals. Waste not, want not and all that sh!t.
Go team Primal University!
When I was on the meal plan in college, I practically lived on sugar-bomb cereal and low-fat milk. Terrible. No wonder I couldn't stay awake in my afternoon classes.
If you just cut out the sweets and grains, you'll be in much better shape than most of your classmates. Optimal, top-shelf Primal isn't feasible for you, but this WOE is totally scalable. Do as much as you can within your limits and ramp it up later when you have more financial flexibility.